1. Field of the Invention
This invention relates to hair-treatment formulations with a certain content of sugar surfactants, selected silicone compounds and pearlescing waxes.
2. Description of the Related Art
Since the beginning of the sixties, silicone compounds have acquired increasing significance as constituents of cosmetic preparations because they improve the feeling the preparations leave on the hair and skin, even in small quantities, are chemically inert, are compatible with virtually all cosmetic ingredients and, finally, are dermatologically safe. Sugar surfactants of the alkyl glucoside or fatty acid-N-alkyl glucamide type show excellent performance properties coupled with particular skin-cosmetic compatibility and, accordingly, are also preferred surfactants for the production of, for example, hair shampoos and manual dishwashing detergents to which substances imparting pearlescence to the formulations through the scattering of light at minute crystals are often added for aesthetic reasons. A review of modern pearlescing formulations was published by A. Ansmann et al. in Parf. Kosm. 75, 578 (1994).
Pearlescing concentrates containing acylated ethylene glycols together with alkyl glucosides are known, for example, from European patents EP-B1 0 376 083 and EP-B1 0 570 398 (Henkel) and from International patent application WO 95/13863 (SEPPIC).
Compositions containing alkyl oligoglycosides, silicones liquid at room temperature and pearlescing waxes are described in European patents EP-B1 0 337 354 and EP-B1 0 398 177 (Kao). Thus, in Examples 2 and 3 for example, EP-B1 0 398 177 discloses shampoo compositions containing 20% by weight of alkyl glucoside, 3% by weight of liquid siloxanes and 2% by weight of pearlescing waxes, namely ethylene glycol distearate. It has been found in practice that formulations of this type are not stable, become inhomogeneous and thicken up. Although their opacity is concealed by the presence of pearlescing waxes, the preparations are not sparkling in their appearance, but dull-looking which is often equated by the consumer with such terms as "spoiled" or "out-of-date". It is clear that any such product will attract little consumer interest despite its satisfactory properties.
European patent EP-B1 0 557 399 (L'Oreal) describes similar preparations which, in addition to alkyl glucosides and pearlescing waxes, also contain silicones. However, the silicones in question are not resin-like substances solid at room temperature which would be of at most only limited use, for example for the production of hair shampoos, because they could easily lead to sticking of the hair strands. Finally, cosmetic preparations containing short-chain alkyl glucosides and hydroxy modified polysiloxanes are known from French patent FR-B 25 42 997 (L'Oreal). However, these preparations do not contain any pearlescing waxes. In addition, pearlescent shampoos containing silicones are disclosed in U.S. Pat. No. 4,559,227 (Dow) and in U.S. Pat. No. 4,704,272 and U.S. Pat. No. 4,741,855 (Procter & Gamble).
Accordingly, the problem addressed by the present invention was to provide pearlescent hair treatment formulations based on the sugar surfactants mentioned and liquid silicone compounds which would be sufficiently stable in storage and which would show a brilliant, finely crystalline pearlescence.